Any area that has limited openings for entry and exit that would make escape difficult in an emergency, has a lack of ventilation, contains known and potential hazards and is not intended nor designated for continuous human occupancy.

"A space that is large enough and so configured that an employee can bodily enter and perform work. Confined spaces have limited or restricted means for entry or exit and are not designed for continuous occupancy. Confined spaces include storage tanks, bins, boilers, ventilation and exhaust ducts, pits, manholes, vats, and reactor vessels." (DOE OSH Technical Reference, http://tis-hq.eh.doe.gov/docs/osh_tr/ch41.html)

A confined space is any space with restricted access or egress where (because of the construction, locations, contents or nature of the work done inside) hazardous, gases vapors, dusts, or fumes may accumulate, or where oxygen may be deficient.

a space that: is large enough and so configured that an employee can enter and perform assigned work; has limited or restricted means for entry or exit; and is not designed for continuous employee occupancy. (See also, Permit-Required Confined Space and Non-Permit-Required Confined Space.)

A confined space is characterized by three conditions (a) limited access; (b) not designed for continuous worker occupancy; and (c) large enough for entry. A confined space which contains any additional serious safety hazards (i.e. known or potential atmospheric hazards, material with the potential for engulfment, steeply sloping floors or other recognized hazards) must be treated as a "permit required confined space" with entry made only in accordance with a written program centered on the issuance and use of an entry permit. (OSHA 29 CFR 1910.146.)

A tank, vessel, open topped tank, or any other enclosed space that is not designed for continuous occupation. A person is considered to be inside a confined space if their head and shoulders are inside the space

A workplace area -- large enough and configured so that a person can bodily enter it -- having limited or restricted egress, and not designed for continuous occupancy. Email Ready for a knowledgeable environmental - pollution insurance professional? Firms with a presence in California Email me now. Email

An area, other than an underground working, that (a) is enclosed or partially enclosed, (b) is not designed or intended for continuous human occupancy, (c) has limited or restricted means for entry or exit that may complicate the provision of first aid, evacuation, rescue or other emergency response service, and (d) is large enough and so configured that a worker could enter to perform assigned work.

A space that (1) is large enough and so configured that an employee can bodily enter and perform assigned work; (2) has limited or restricted means for entry or exit (e.g., tanks, vessels, silos, storage bins, hoopers, vaults, and pits are spaces that may have limited means of entry); and (3) is not designed for continuous employee occupancy.

Has one or more of the following characteristics: 1) Contains or has the potential to contain a hazardous atmosphere. A hazardous atmosphere would be created by any of the following, including: a) Vapors exceed 10% of the lower flammable limit (LEL) b) Airborne combustible dust exceeds its LEL c) Atmospheric oxygen concentrations below 19.5% or above 23.5% d) Atmospheric concentration of any substance for which a dose or PEL is published and which could result in employee exposure in excess of these values e) Any other atmospheric condition which is immediately dangerous to life or health (IDLH) 2) Contains a material that has the potential for engulfing an entrant. 3) Has an internal configuration such that a person could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross section. 4) Contains any other recognized serious safety or health hazard.

Confined space is a term from labor-safety regulations that refers to an area whose cramped conditions make it dangerous. Confined spaces present special hazards to workers, including risks of toxic gas accumulation, fires, falls, flooding, and entrapment. A utility tunnel, the inside of a boiler (only accessible when the boiler is off), the inside of a fluid storage tank, and a small underground electrical vault could all be classified as confined spaces.